1. Field of the Invention
The present invention relates to ear couplers or earphones that cover the ear to create a desired acoustic environment.
2. Background of the Invention
It is inherently difficult to determine hearing impairment in infants, since they cannot participate in traditional hearing tests which require subjects to indicate whether they can hear various sounds. However, if hearing impairment is not detected until the infant grows into a toddler or child, then the potential for long-term disability increases, since the child""s language skills will have developed before remedial measures have been undertaken. The optimal time to screen for hearing impairment is immediately after birth, both because early detection allows for early treatment, and because parents often fail to bring their children in for later appointments.
Devices and methods have been developed to evaluate infant hearing by subjecting an infant to an aural stimulus, and then measuring the electroencephalographic or otoacoustic response to that stimulus. These devices and methods depend on the creation of the proper acoustic environment about the subject""s ear, so that ambient noise does not interfere with the hearing evaluation, and so that the stimulus has the appropriate duration, amplitude, and frequency content.
To create the desired acoustic environment, earphones or ear couplers have been used. Information relevant to previous ear couplers can be found in U.S. Pat. Nos. 5,826,582, 4,930,520, and in U.S. patent application Ser. No. 09/395,799. Although many of these devices have worked well, they can sometimes become detached from the subject""s head, because of the variable and irregular surfaces surrounding the ear, and because infants tend to move during testing. Additionally, with previous ear couplers, the assembly that houses the stimulus-producing transducer tends to tug the ear coupler away from the ear. Existing ear couplers are also relatively expensive to manufacture, in part because they require production or assembly of more than one part.
It is therefore desirable to construct an ear coupler that is better able to remain attached to the subject""s head, and that is not subject to being tugged off the head by forces acting on the transducer housing. It is also desirable to design a one-piece ear coupler that can be inexpensively manufactured by injection molding or other suitable processes.
The present invention is a transparent one-piece ear coupler, with an internal chamber that creates a tuned acoustic environment about the subject""s ear, with a port to accommodate a transducer, and with a flange positioned around the periphery of the coupler to attach the coupler to the subject""s head.
Other features of the preferred embodiment of the present invention include a tab to facilitate removal of the ear coupler, and a mark or target on the coupler to help ensure proper alignment over the subject""s ear. The coupler is generally D-shaped, and is designed so as to fit on either ear. Preferably, the coupler is made of transparent Rimflex(copyright) thermoplastic elastomer, although other flexible, transparent materials could be used. The bottom wall of the coupler contains waffle-shaped or other surface features, which add rigidity and create the desired acoustic characteristics of the chamber.
The exterior wall of the coupler is ribbed to provide means to securely lock in place the housing that contains the transducer. The side of the flange in contact with the skin contains hydrogel or another adhesive substance to stick to the subject""s head. The interior surface of the flange may also contain waffle-shaped or other surface features for improved adhesion of the hydrogel to the Rimflex(copyright), although no such extrusions are provided in the preferred embodiment of this invention. The walls of the coupler are of sufficient thickness to resist crushing, and to provide the desired acoustic environment about the subject""s ear.
The housing that contains the transducer, known as an acoustic transducer assembly (ATA), securely and positively fits into the port that enters into the internal chamber. The ATA latches onto ribs on the sides of the coupler, and can be rotated up or down while in use, so that the length of the ATA can placed either above or below the center of the coupler.
Before being attached to the subject""s head, the ear couplers are attached to release paper. Preferably, the adhesive that secures the ear couplers to the release paper (and to the subject""s head) is a hydrogel, which can be selectively applied only to the flange of the ear coupler during manufacture, thereby minimizing waste. There are holes in the release paper, centered over the chamber of the ear coupler, to help the user hold the coupler while the ATA is being inserted.
In operation, the ATA is inserted into the port, and the ear coupler is removed from the release paper and placed on the subject""s ear. The adhesive on the flange sticks to the subject""s head, and because of the unique features of the invention as disclosed herein, the ear coupler will tend to stay affixed to the infant""s head, even if he or she moves during testing. The tab helps remove the ear coupler from the release paper, and helps remove it from the subject""s head when the testing is complete.